Control mechanism for temperature, humidity, and the like



Oct. 1, 1940. c. A; o'r'ro y 2,215,551

CNTROL MECHANISM FOR 'IEM1"'".|RA'1U\`E,- HUMIDITVY., AND THE LIKE Filed Feb.y 195e Patented ocr. 1,1940

2,216,651 CONTROL MEcnANrsM Fon. 'rEmEnA'rUna HUMID ITY, AND THE LIKE Carl A. Otto, Milwaukee, Wis., assignor to Johnson Service Company, Milwaukee, Wis., a corporation of Wisconsin Application February 3, 1938, Serial No. 188,566

' 6 Claims. t (Cl. 236-79) This invention relates to the control of atmospheric conditions such as temperature, humidity and the like, and is directed to the automatic control means through which an element or a pair of elements, responsive to atmospheric conditions, exercise a controlling function. In the air conditioning art various schemes for variably energizing a pressure motor in response to the indication of an element which changes in form or dimension in response to atmospheric conditions; have been used. y

One type which has enjoyed some commercial popularity delivers air from a source of air under substantially uniform pressure through a nozzle in such away as to convert the pressure head of the airv so supplied into velocity head. The jet issuing from the nozzle is a free jet for a limited distance, and is directed through an orifice into a pressuremotor which controls some apparatus such as a humidier, a heater, a cooler or other air conditioning apparatus.

An element responsive to an atmospheric condition, such as temperature or humidity, serves to vary the pressure head developed in the motor by the action of the jet. 'I'his may be accomplished in a number of ways. The nozzle may be shifted so that the jet is not directed precisely into the orice leading to the motor, or the nozzle may be moved toward or from the orifice to vary the length of the free path of the jet, or the two effects above mentioned may be combined or an interce ting means may be interposed betweenl the or ce andthe jet serving to intercept the jet in a variable degree and thus vary the proportionof the kinetic energy of the jet which is converted into pressure head in the motor. These various means are knownin the art and to a certain extent are equivalents.

The resent invention is' based on the concept that b varying the pressure head on the iluid supplied to the nozzle, Vthe total energy of the jet may be varied. This variation in pressure head may be eilected by automatic means which respond 'to a condition different Jirom that which controls the action of the nozzle, thus producing a modifying control, or a conjoint control in response of two variables.

The phrase condition diierent used above may mean diilerent in kind or diierent in location. or both. For example, control might be in response to dry bulb temperature at two dierent places,- such as indoors and outdoors,` or it might beunder control of temperature and humidity at the same place orat di'erent places.

The inventive concept can also be applied to a simple selectivev control providing selective readjustment of the control point of the responsive is caused to respond to two different variable l quantities; v

Fig. 2 is a similar view'of a modiiled system in which a manually set device serves to change the point at which an element responsive to variable quantity responds.

Fig. 3 showsa modiilcation of the nozzle mechanism available for use with either the structures of Fig. 1 or Fig.,2;

Fig. 4 shows another modiilcation; and

Fig. 5 is av detail of the controlling vane shown in Fig. 4.`

Reference will first be made to Fig. 1. The supply of pressure to the nozzle is controlled by a relay thermostat of the type shown in the patent to Otto No. 1,500,260, July 8, 1924, but this device is given a special adjustment, diierent from` that normally used. so that it supplies air at all times under a positive but variable pressure. The body of the thermostat shown at 6 has an air supply 'I through which compressed air from any suitable source is supplied at a pressure slightly higher than the maximum pressure which it is desired to supply to the nozzle hereinafter described.' For purposes of discussion we shall assume that the` maximum pressure head to be supplied to the nozzle aforesaid is 30. pounds per square inch gage.

From the supply "I, air is fed-past a restricting needle valve 8 to a chamber 9 on the front side" vof the diaphragm II.

A leak port I2 leads from this chamber to the atmosphere and its capacity is varied by a valve I3 which is shifted toward and from the leak port I2 by a thermostatic bar I4. 'I'he bar I4 is intended to typify any element responsive to an atmospheric condition.

Thediaphragm II is connected at its center to a smaller diaphragm I5 by 'means of the hub member I6 which has an exhaust port I1 discharging into the space between the diaphragms. This space is vented to atmosphere at I8. As the hub I6 is moved inward by pressure on the forward side oi the diaphragm, it ilrst engagesa combined Supply and exhaust valve I9.in such a way that .the valve closes the exhaust port I1, after which continued inward' movement forces the available in the art to supply line 23 with fluid under a pressure which varies in response to a variable quantity. An example of such variable quantity is temperature affecting the thermostatic bar II4.

Unlike gradual thermostats as heretofore used under the Otto patent above identified, the needle valve 8 is so adjusted that when the leak port I2 is wide open, a substantial pressure exists in chamber 9. For purpose of discussion, and without implying any limitation, it will be assumed that when the leak port I2 is wide open the pressurein line 23 will be l5 pounds gage, and when the leak port is closed it will be 30 pounds gage. Because of the differential effect oi the unequal diaphragms II and I5, the pressure in the line 1 should be somewhat above 30 pounds gage.

Line 23 supplies air to a nomle 24 which is hinged at 25 sofas to be movable with a lateral swinging motion into and out of alinement with an orifice 26 connected 4by a pipe with a bellows motor 21. This motor includes a return spring 28. To shift the nozzle 24 use is made of a thermostatic bulb 29, which in response to varying temperature, develops a varying pressure in the space in housing 3| beneath the flexible diaphragm 32. 'Ihe center of the diaphragm 32 is connected by link 33 with the nozzle 24. Motion of the diaphragm under pressure developed in the bulb 29 is resisted by a coiled compression spring34.

The motor 21 is mechanically connected to operate the control mechanism of a heater, cooler, humidifier or other air conditioning apparatus. The primary control is effected by the bulb 29, but the bar I4 exercises a secondary control by varying the pressure head in the line 23 and consequently the velocity head of the jet issuing from the nozzle 24. This offers a simple way to control in response to two variables.

When it is desired to set a thermostat for two control points, as is done for example in the familiar night and day thermostats, I may adopt the arrangement shown in Fig. 2 in which air is supplied at two different pressures. In Fig. 2 I show two reservoirs 35 and 36 which are kept charged at 15 pounds gage and 30 pounds gage, respectively. 'I'hese are selectively connected by a manually operated, three-way cock 31 with the supply line 23a leading to the nozzle 24a. The remaining parts in Fig. 2 correspond to those in Fig. 1 and are similarlynum-bered with the letter a..

'I'he parts to the right of the line A-A in Fig. 1, and similarly the parts to the right of the line B`B in Fig. 2, may be modified as indicated in Fig. 3. Parts which correspond to similar parts in Figs. 1 and 2 bear the same referencenumerals but with the distinguishing letter b. i

The hinge 25h is so arranged that the nozzle 24h moves toward and from the oriiice 26, thus varying the length of the free jet -between the nozzle and the orifice. y If the radial distance from the nozzle 24b to the pivot 25h be relatively short, the swinging motion 0I the nozzle will change direction as well as distance, but if the radial distance is increased, the variation of direction can be reduced until it becomes negligible. Thus, Fig. 3 illustrates the mechanical aspects of a construction in which both interval and direction are changed or in which interval alone is changed. the difference being a matter of degree and depending on the radial distance above defined.

In Fig. 3 the spring 34h acts in tension instead of compression, but this is without functional significance as it is possible to arrange springs in any desired manner.

In Figs. 4 and 5 the nozzle 24e has a fixed relationship to the nozzle 25e. 'I'he remaining parts, identified by reference numerals with the distinguishing letter c, correspond to similarly numbered parts in the other figures.

'I'he vane 38 mounted on the pivot 39 is arranged to be shifted by a responsive element 29o which corresponds generally to the thermostatic bulbs 29, 29a and 29h of the other figures. The swinging motion of the vane 3B causes it to intercept a variable portion of the jet' issuing from the nozzle 24o, and thus varies the pressure developed in the motor 21c. I

The power of the motor 21 in Fig. 1, and its analogue in the other figures, may be multiplied by any suitable means, for example, by the relays commonly used in the art, but since no patentable novelty is predicated on the use of a relay it seems unnecessary to describe this structure in detail. As far as the present invention is concerned it suilices to state that its presence is not incompatible with the structure of the present invention.

Generally stated, the present invention is directed to modifying the action of or imposing a secondary control on thermostatic and like devices of the nozzle and orifice type by varying the pressure head o1' the pressure fluid supplied to the nozzle for the purpose of varying the total velocity head of the jet issuing from the nozzle.

Various forms of the nozzle and orifice control are known, and several havev been illustrated. The drawing and description are meant to be exemplary and not limiting, the scope of the invention being defined in the claims.

1. The method of regulating a device for conditioning the atmospl'ime which consists in forming a jet of fluid having energy in the Vform of velocity head; varying said velocity head in accordance with an atmospheric condition; converting a portion of said velocity head into pressure head; varying the portion so converted in accordance with another atmospheric condition; and regulating said conditioning device by variation of the resulting pressure head.

2. The method of controlling a device for conditioning the atmosphere which comprises directing a free jet of fluid under velocity head through an orifice into a closed chamber', whereby pressure is developed in the chamber; controlling said device by changes of chamber pressure; and concurrently changing the chamber pressure in accordance with changes in two atmosphericconditions by varying said velocity hea'd in accordance with one condition, and the coaction of the jet with the orifice in accordance with the other condition. 3. Means for actuating dampers, valves an the like comprising in combination, a pressure motor having an orifice; a. nozzle adapted to direct a free jet of pressure uid into said orice whereby iiuid pressure is developed in said motor; means for supplying iluid under pressure to said nozzle; means responsive to an atmospheric condition i'or varying the coaction of said nozzle and oriflce whereby the pressure in the motor is varied; and means for concurrently varying the pressure under which iluid is supplied to said nozzle.

4. Means for actuating dampers, valves and the like' comprising in combination, a pressure motor having an oriiice; a nozzle adapted t0 direct a iree jet o! pressure iluid into said orifice whereby iluid pressure is developed in said motor; means for supplying iluid under pressure to'said nozzle; means responsive to an atmos pheric condition for varying the coaction of said nomle and orifice whereby the pressure in the motor is varied; and means responsive to a different atmospheric condition for concurrently varying the pressure under which iluid is su plied to said nozzle. v

45. Means for actuating dampers, valves and the like comprising in combination, a pressure motor having an oriiice; a nozzle adapted to direct a free jet of pressure iiuid into said orice whereby fluid pressure is developed in said mov tor; means for supplying iluid under pressure to said nome; means responsive to an atmospheric condition for shifting said nozzle relatively to said oriiice whereby the pressure in the motor is' varied; and means for concurrently varying the pressure under which fluid is supplied to said nozzle. i

6. Means for actuating dampers, valves and the like comprising in combination, a pressure motor having an orifice; a nomle adapted to direct a free 'jet of pressure iiuid into said oriilce l whereby fluid pressure is developed in said motor; means for supplying uid under pressure to said nozzle; means responsive to an atmospheric condition i'or intercepting a portion of the jet directed by said nozzle toward said orifice whereby the pressure in the motor is varied and means responsive to a different atmospheric condition ior concurrently varying the pressure under which iiuid is supplied to said nozzle.

om A. o'i'ro. 

